Drop bottom mine car



June 26, 1951 R. A. SHIELDS DROP BOTTOM MINE CAR Filed March 7, 1947 June 26; 1951 R, A SHlELDS' DROP BOTTOM MINE CAR Filed March v 1947 Patented June 26, 1951 UNITED STATES PATENT YOFFICE DRorBo'rfroM MINE CAR Application March 7, 1947, Serial No. 732,978

(Cl. d-253) 17 Claims.

This invention relates to mine .cars in general and in particular to drop bottom -mine cars which are intended for use with. coal. or other mineral that breaks readily.

With certain types of minerals and coal, dropping of the material into .the bins causes considerable monetary loss due to breakage Yof thematerial. This is .particularly `.true .of .coal where .the larger sizes bring a much higher price than do the small-er sizes. Attempts have been made to provide drop bottom cars lwhich .place the coal in the bins with a minimum of breakage but with all .cars .as built at presen-t the doors must open a lconsiderable amount before discharge .of coal can take place. Building up .the sides of the doors prevents leakage of .coal at the sides when in the preliminary dropped positon, but, due to the relatively large opening required, coal spills over the ends of the doors and is. ground to a powder on the skid .plates `placed at the approach end of the bin or hopper. With the -doors as previously built means independent .of the door had to be provided to control the` movements .of the doors and these means were usually carried by the car and .acted on the door .tocontrol'its movement independentof its hinging action. It is an object, therefore, of the present invention to provide a drop bottom door for :mine cars having all controlling mechanism connected to the door and carried thereby lto cause the desired shifting movements of the door.

A further object of the invention is the provision of door .control means which will permit sequential opening of the doors of a car upon a slight opening movement `of the doors, which movement is insuicient to permit .discharge of` coal or other material over the ends of the doors.

A still further objectof the invention is the provision of a drop bottom mine car having inter.- changing doors capable of opening following a slight opening movement of the rearwardly adjacent door. f

Yet another object of the invention is the provision of va drop bottom mine car having interengaging doors with an overlap -of approximately one inch, yet which become disengaged uponan opening movement of approximately six degrees of the rearwardly adjacent door.

These and other objects of the invention will be apparent VVto persons skilled in the art from a study -of the following description and accom.- panying drawings, in which Figs. 1 and 1A taken .together com-prise'a side elevational View of ,a complete .car with aparts broken away to better disclose the constructions;

Fig. 2 is an end view of the car with parts broken away to better show the hinging means for one of the doors;

Fig. 3 is a plan view of a portion of the car with parts broken away to .disclose the door hinging;

Fig. 4 is a sectional View taken through the car and showing the doors in preliminary opening position, and

Fig. 5 is a sectional view showing one of the doors in substantially full open position.

Referring now to the drawings in detail it will be seen that the car is made up of a forward end F, a rearward end R joined by side walls 4. These side walls are connected to and supported by inner sills 6 and outer sills 8 forming spaced pairs of sills supported on wheel and axle assemblies W preferably by springs or other resilient means I0. The end walls F and R are connected to the end sill structures which join the side walls and in turn have connected thereto bumper and coupler elements B. In order to rigidly tie the car side walls together, deflector hoods I2 are provided and these hoods extend across the car at the points where through axles would normally have appeared, but which are absent due to the .useof stub axles inthe wheel and axle assemblies. These `cross ties and deflectors I2 are welded or otherwise rigidly attached to the inner faces `of the side sills E and to the wheel hood housings I4, which in turn are rigidly connected to the side walls of the car. The side walls of the car obviously can be sloping as shown in Fig. 2, or vertical, or of any other desired form, the sole consideration being that they discharge any load resting thereon into the space between the side sills. The end structure R, previously referred to, has attached thereto a release hook H normally held in the full line position of Fig. 2 by a spring or other device I6. The hook is adapted to be moved to a released position by trackside means striking the release arm I8 which is connected to the hook and car end structure. It is, of course, obvious that various other types of door release mechanism may be used but, since the operation of the type shown is well understood, it will be used for purposes of illustration.

The space between the side sills 6 and end structures F and R is adapted to be closed by a plurality of doors mounted for swinging movement longitudinally of the car. The forward door 2 0 has its forward edge rolled around a transversely extending bar 22 carried by the side sills beneath a sloping shed or protector plate 24 forming part of the forward end structure. This `forward door '20 extends rearwardly and downwardly to a low point 26, thence upwardly and rearwardly to terminate in a substantially horizontal portion 28 forming the free edge of the door. The sides of the door are formed by plates 30 adapted to closely engage the inner surface of the side wall structures and form a Dan shaped door with sides of sufficient height so that when the door is dropped to its preliminary open position, the sides will not drop below the lower edge of the side sills 6 as clearly shown in Fig. 4. In this manner spillage of coal at the side edges of the door is prevented. The intermediate door or doors 32 and rear door 34 have their forward edges formed substantially identical and as shown are formed with a substantially horizontal forward portion 36, a downwardly and rearwardly inclined portion 38 positioned at a relatively steep angle and a main downwardly and rearwardly sloped portion 46 which/extends to a low point 42. From the low point of the doors 32 and 34 the plate slopes upwardly and rearwardly as at 44A to the free edge of the door. In the case of the intermediate doors 32, the free edge of the door is formed by directing the free edge of slope 44 rearwardly as at 46 to provide a substantially horizontal portion adapted to overlie and rest upon the forward portion 36 of the rearwardlyadjacent door. The rear door 34 may have its slope 44 provided with a similar edge but in the instance shown the free edge or slope 44 has attached thereto a lug 48 adapted to be engaged by the hook H previously referred to. The side edges of doors 32 and 34 are formed by upwardly extending plates 50 securely welded or otherwise attached to the sloping portions 38, 46 and 44 and these sides are ofsuicient height as `toalways be located above the bottom edges of the sills 6 except when the doors are dropped over the bins or hoppers. As clearly shown in Fig. the edge portions of flat part 36 and parts of slope 38 are cut away as at 66 and these portions adjacent the cut away portion are tied together by gusset plates 62 welded or otherwise secured to the lsloping portion 38 and at portion 36. These gusset plates 62 are pierced to receive a forwardly disposed bolt 64 and a rearwardly disposed bolt 66 providing respectively forward and rearward axes for the door. Bolts 64 and 66 are pivotally connected to the upper ends of a forward link 68 and a rearward link 10, the lower ends of which are pivoted on forward axes 12 and rearward axes 14. These forward and rearward axes 12 and 14 are provided with bolts or pins extending through the links and through the side sills 6. As most clearly shown in Figs. 1 and 2 the axes 64 and 66 are located forwardly and rearwardly respectively of vertical planes through axes T2 and 174. `.T n other words, planes through axes 64 andy l2 -andthrough axes 66 and 14 will converge downwardly. It is, of course, obvious that slight rearrangements in the positions ofthese axes may be made, but it is to be understood that each change willproduce a different action of theV connected door. In order to clear the links 68 and gusset plates 62, the rear side edges of doors 20 and 32 will be cut away slightly as indicated at 80 in Fig. 3. Also, in order to yprevent any possibility of doors 32 following door 34 in the opening movement and prior to disengagement between-edges 46 and 36, a lug 82 is attached to the side sill and engages in a shallow notch 84 formed in the side edges 50 of doors 32. These lugs and notches perform no function during the closing of the doors by the door ramp (not shown) but merely prevent the doors 32 from following the 4 next rearward door in its opening movement until the forward edge of the rearward door has cleared the free edge of the forward door. With the doors as shown the forward edges of doors 32 and 34 are supported upon upwardly diverging or downwardly converging struts 68 and 10 which, due to the connection to the door and side sill, form quadrilaterals preventing any relative shift of the door except that accompanied by rotation.

For illustration purposes, the struts 68 and 1l] have been shown as two and one-half inches long, with the spacing between axes 12 and 14 four inches and. that between axes 64 and 66 as four and one-half inches. From such a relationship it can be calculated that the door as mounted in Fig. 1 is hinged about a trunnion point approximately twenty inches below the door. It is to be remembered, however, that this is only true for the normal supported condition of the door and changes instantly when the door starts to open. Y However,v it will serve to clearly indicate the movement of the door in its initial opening. When the car, with the doors in closed position as shown in Figs. 1 and 1A, moves into the dumping station, the hook H will be disengaged from the lug 48 of rear door 34 and this door can then immediately drop to the position showny in Fig. 4, at which position it is supported upon:

a skid plate S indicated by the line of Fig. 4 and which is located approximately an inch and a half below the rail or track surface T upon which the wheels rest. With such a placement of the skid plate the low portion of the doors drops approximately two and one-half inches or roughly four and one-half degrees for a thirty-six inch door. During dropping of the door 34 to the position of Fig. 4 links or struts 68 and 10 rotate to the position shown in Fig. 4, but since the links converge downwardlywith a normal support at a virtual axis twenty inches below the door, the slight dropping of the door causes a considerable shift of ,the door to the rear of the car. This large rearward shift of the door with slight rotational movement causes the flat portion 360i door 34 to move from beneath the flat portion 46 of door 32. As soonas this has opened door 32 can drop, moving rearwardly so that at portion 28 of forward door 20 will clear the at portion of intermediate door 32. It will be seen that when the doors are in the preliminary open position of Fig. 4, the point of intersection of the planes through axes 64 and 12 and 66 and 14 will be nearer the door than in the normal position. This means, of course, that the angle of up- -ward divergence or downward convergence between the links has increased. As the doors move off of the skid plate S and into the hopper (not shown) they may swing to their open position as shown in Fig. 5. During this opening the links or struts 10 will move a more or less constant speed with axis 66 rotating in an arc about axis 14. The axis 64, however, will rotate around axis 12 at a variable rate of speed since, due to the position of the axes, 64 approaches axis 'I4 and then recedes to the position as shown in Fig. 5; In other words, while strut 10 rotates about axis 14, strut 68 oscillates about axis 12. From a study of Fig. 5 it will be'seen that the links 68 and 'Hl are substantially parallel in their full' open position. 'Ihis means that the upwardly diverging links support the door in normal position and during opening the angle of upward divergence increases constantly toa maximum, then constantly and approaching innity as a limit,

in other words, Vwith the links substantially parallel. From this it will 'be 4seen that a positive check is placed on the doors preventing their swinging and slapping with consequent binding as is .now met with under `the present type of door hinging.

vDuring vclosing of the doors a reverse action takes place, that, is the links B8 and 1-0 move from their substantially parallel Aposition of Fig. 5 to a position in which they diverge Adownwardly and this angle of divergence increases constantly bringing axis '64 toward `axis 14 4until it reaches the limiting position, after which the .links Ydiverge upwardly with the angle decreasing constantly Auntil it reaches the 'minimum position with the doors in their fully raised condition as shown in Figs. 1 and 1A.

From the preceding description of the structure and its operation it -will be seen that va large overlap can be obtained between the doors and the doors shift Vrearwardly a large vamount -with a very slight degree of .open-ing, which, accompanied by the shape of the doors and the cooperating car structure, prevent discharge of coal from the cars until they lhave vreached vthe dumping station. Also, with the -linkage as show-n, the doors are positively checked in ltheir swinging movements, thereby preventing the doors from swinging into each -other and locking in an open lposition preventing further movement of the car until the doors are disengaged. Likewise, during closing of the doors the linkages will -positively shift the doors to their forward position `beneath the next forward door and without the use of any exterior guide surfaces on the car -or trackside. While the car and doors have vbeen described more or less in detail, it will be -obvious that various modifications, vother than those shown and described, may bemade and all such modications and rearrangements of parts are contemplated as will fall within .the scope fof the following claims defining my invention.

What is claimed is:

`1. A Ydrop bottom dump apparatusy comprising a frame, a forward door and arearward door, transversely spaced apart pairs of struts pivotally supporting each door adjacent its forward edge on the frame with the struts of each Vpair disposed longitudinally vof the frame whereby each door may swing downward at its rearward edge for opening, -means vholding vsaid rearward door closed, and means on the Arearward edge of said forward door adapted to engage the forward edge of said rearward door to hold said forward door closed.

2. A drop bottom dump apparatus comprising a frame, a forward door and Va rearward door, transversely spaced apart pairs -of struts pivotally supporting each door adjacent its forward edge on the frame with the struts Aof each pair disposed longitudinally of the frame whereby each door may swing downward at its rearward edge for opening, means holding said `rearward door closed, and means on the rearward edge of said forward door adapted to engage the forward edge of said rearward door to hold said forward door closed, said last named means moving fout of engagement with said rearward door whereby said forward vdoor may open upon release of said first named means and downward swinging -of said rearward door through an angle of less than six degrees. 1

3. A drop bottom dump apparatus comprising a-supporting frame, wheels supporting the frame for travel along rails, a plurality of doors :interengaging when closed `and normally @cooperating with the frame to carry lading., and transversely spaced apart pairs'of struts pivotally supporting the forward edge of one of said doors on the frame with the :struts of each pair disposed longitudinally of the frame, said struts being so constructed .and arranged as to provide a transversely extending virtual pivot axis for said -closed door below the lowermost plane of the rails.

4. A vdrop bottom dump apparatus comprising a supporting frame, wheels supporting the frame .for travel along rails, a plurality of doors interengaging when yclosed and Ynormally cooperating with the frame to carry lading, and longitudinally swinging linkage pivotally supporting the forward edge of one of -said doors-on the frame and providing a transversely extending `virtual pivot axis for said closed door located below Vthe lowermost plane of the rails.

5.'A -drop bottom .dump apparatus comprising a supporting frame, wheels supporting the yframe for travel along rails, a plurality of doors interengaging when closed and normally cooperating with the frame to carry lading, and longitudinally swinging linkage supporting the forward edge of one of said doors and providing a transversely extending virtual pivot axis for the door when vsubstantially closed which is located below the plane of the frame and which is located above the plane of the frame when the door is in substantially `open position.

-6. A .drop bottom dump apparatus comprising ,a supporting frame, ,a plurality of doors interengaging when closed and normally cooperating with the frame to carry lading, and 'a pair of longitudinally swinging struts pivotally supporting each forward side edge of one of said doors on said frame, the individual struts of each pair being spaced longitudinally of the frame.

7. A drop bottom dump apparatus comprising `a vsupporting frame, a plurality of doors interengaging when closed and normally cooperating with the frame to carry lad-ing, and a pair of longitudinally swinging pivotally mounted struts supporting each forward side-edge of one vof :said doors on said frame, the individual struts of each 'pair being spaced longitudinally of the frame and pivoted to said frame adjacent `their lower ends and `to said one door adjacent their upper ends.

:8. A drop 4bottom dump apparatus comprising a supporting frame, a plurality of doors interengaging when closed and normally cooperating with the frame to carry lading, and a pair of longitudinally swinging pivotally mounted struts supporting each forward side edge of one of said doors on said frame, said struts being pivoted to said frame at longitudinally spaced apart points adjacent their lower ends and to said one door at more widely spaced apart longitudinally disposed points adjacent their upper ends.

y9. A drop bottom dump apparatus comprising a supporting frame, a plurality of doors interengaging when closed and normally cooperating with the frame to carry lading, vand a pair of longitudinally swinging pivotally mounted struts supporting each forward side edge of one of said doors on said frame, said struts being pivoted at longitudinally spacedpoints to said frame adja cent their lower ends .and to said'one door adjacent their upper ends, one of said struts `ofeach pair `rotating about its pivotal mount Yon the frame and `the Aother `of said struts -ofeach pair oscillating about its pivotal mount on the frame during opening of said one door.

10. A drop bottom mine car comprising, a sup porting frame, a rearward door, a pair of struts pivotally mounted on said frame adjacent each forward side edge of said rearward door and /being pivotally connected to said door to support the forward edge thereof, the individual struts of each pair being spaced longitudinally of lthe car, a forward door pivotally mounted on said frame and having its rearward edge in supporting engagement with the forward edge of said rearward door, and means to support the rearward edge of said rearward door.

11. A drop bottom mine car comprising, a supporting frame, a rearward door, a pair of struts pivotally mounted on said frame adjacent each forward side'edge of said rearward door and being pivotally connected to said door to support the forward edge thereof, the individual struts of each pair being spaced longitudinally of the car, a forward door pivotally mounted on said frame and having its rearwardl edge in supporting engagement withlthe forward edge of said rearward door, and means to support the rearward edge of said rearward door, said struts being upwardly divergent whereby the virtual pivotal axis for said closed rearward door is located a substantial distance below said frame.

12. A drop bottom mine car comprising, a supporting frame, a rearward door, a pair of struts pivotally mounted on said frame adjacent each forward side edge of said rearward door and being pivotally connected to said door to support the forward edge thereof, the individual struts of each pair being spaced longitudinally of the car, a forward door pivotally mounted on said frameand having its rearward edge in supporting engagement with the forward edge of said rearward door, and means to support the rearward edge of said rearward door, said struts being so constructed and arranged as to shift said rearward door out of supporting engagement with said forward door upon less than a six degree opening movement of said rearward door.

' 13. A drop bottom mine car comprising, a supporting frame, a rearward door, a ypair of struts pivotally mounted on said frame adjacent each forward side' edge of said rearward door and being pivotally connected to said door to support the forward edge thereof, the individual struts of each pair being spaced longitudinally of the car, a forward door pivotally mounted on said frame andl having approximately a one inch width along its rear edge in supporting engagement with the forward edge of said rearward door, and means to support the rearward edge of said rearward door, said struts being so constructed and arranged as to shift said rearward door out of engagement with said forward door upon less than a four inch drop of the rear edge of said rearward door.

14. A drop bottom mine car comprising, a supporting frame, a rearward door adapted to rotate down to open position, a pair of struts pivotally mounted on said frame adjacent each forward side edge of said rearward door and being pivotally connected to said door to support the forward edge thereof, the individual struts of each pair being spaced longitudinally of the car, a forward door pivoted to said frame and adapted to swing down to open position, a rear portion of said forward door engaging and supported on the forward edge of said rearward door when closed, and means to retain said rearward door in closed 8 position, said struts diverging upwardly from their pivotal mount on the frame to thereby produce a large rearward shift of the rearward door upon a slight opening rotation thereof.

15. A drop bottom mine car comprising, a supporting frame, a door adapted to rotate downward from a closed to an open position about its forward edge, a pair of longitudinally swinging struts pivotally connected to the door adjacent each forward corner thereof and being also pivotally connected to the frame at points below their pivotal connections to the door, the individual struts of each pair being longitudinally spaced and diverging upwardly to support lthe door in closed position and diverging downwardly to support the door in substantially open position.

16. A drop bottom mine car comprising, a supporting frame, a door adapted to rotate downward kfrom a closed to an open position about its forward edge, a pair of longitudinally swinging struts pivotally connected to the door adjacent each forward corner thereof and being also pivotally connected to the frame at points below their pivotal connections to the door, the individual struts of each pair being longitudinally spaced and diverging upwardly to support the door in closed position and diverging downwardly to support the door in substantially open position, the angle of upward divergence of said struts increasing constantly during the initial opening of the door and the angle of downward divergence decreasing constantly during the final opening movement of the door to thereby check the swinging of the door.

17. A dropbottom'mine car comprising, a supporting frame, a door adapted to rotate downward from a closed to an open position about its forward edge, a pair of longitudinally swinging struts pivotally connected to the door adjacent each forward corner thereof and being also pivotally connected to the frame at points below their pivotal connections to the door, the individual struts of each pair being longitudinally spaced and diverging upwardly to support the door in closed position and diverging downwardly to support the door in substantially open position, the angle of upward divergence of said struts increasing to a maximum then changing to an angle of downward divergence decreasing to substantially Zero during rotation of the door from closed to open position.

ROBERT A. SHIELDS.

REFERENCES CITED The following referencesare of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,387,962 Baerwaldt Aug. 16, 1921 1,407,740 Evans Feb. 28, 1922 1,606,517 Dixon Nov. 9, 1926 1,817,773 Sipe Aug. 4, 1931 1,888,345 Cummings Nov. 22, 1932 2,250,555 Schroeder July 29, 1941 OTHER REFERENCES Elements of Mechanism, by Schwamb, Merrill and James. Wiley & Sons, Inc. N. Y., 1921. Pages 221-229 inclusive, and 244-248 inclusive. (A volume of this reference, privately owned in Div. 34 of the Patent Office, is available for photostatic copies.) f 

